Simulating cement microstructural evolution during calcium leaching

Calcium leaching is one of the important degradation mechanisms causing dissolution of the crystalline phases such as, AFm, portlandite increasing capillary porosity. Further it leads to decalcification of an amorphous C-S-H phase causing increase in the gel porosity and in turn degrading the long term performance of concrete structures. In this...

Ageing of portland cement concrete cured under moist conditions

Deterioration of microstructure in cement concrete will cause changes in the transport properties of the concrete. Transport properties at different ages of the concrete provide information about the microstructural changes of the material. A way to measure the transport properties, i.e. the chloride diffusion coefficient, in the laboratory is...

Lattice Boltzmann based multicomponent reactive transport model coupled with geochemical solver for scale simulations

A Lattice Boltzmann (LB) based reactive transport model intended to capture reactions and solid phase changes occurring at the pore scale is presented. The proposed approach uses LB method to compute multi component mass transport. The LB multi-component transport model is then coupled with the well-established geochemical reaction code PHREEQC...

Multiscale lattice fracture model for cement-based materials

Cracking in cement-based materials is usually not easy to predict, because of the complexity of their microstructures. Concrete is a composite material of mortar and coarse aggregates, and mortar consists of cement paste and sands. The fracture processes in these materials are related, and this paper aims to reveal the relationship by developing...

Modeling fracture behavior of cement paste based on its microstructure

Concrete is a composite construction material, which is composed primarily of coarse aggregates, sands and cement paste. The fracture processes in concrete are complicated, because of the multiscale and multiphase nature of the material. In the past decades, comprehensive effort has been put to study the cracks evolution in concrete, both...

Reliable concrete repair: A critical review

This paper highlights the importance of achieving durable and long-term predictable repair of reinforced concrete structures. The performance of concrete repair in past and current engineering practice, including all types of repair and application of different materials, is often unsatisfactory. One of the reasons for this lays in the fact that...

Influences of mineral composition of cement on the mechanical properties of cement paste

Multiscale modeling scheme for cementitious materials

3D Simulation of micromechanical behavior of cement paste

Numerical modeling of fracture processes of brittle materials, such as cement paste, mortar, concrete and rocks, started in the late 1960s when the discrete and smeared cracking models were introduced. In the 1990s, Schlangen and van Mier proposed another numerical model to compensate the drawbacks of the discrete and smeared cracking models,...

Development of engineered cementitious composites with limestone powder and blast furnace slag

Nowadays limestone powder and blast furnace slag (BFS) are widely used in concrete as blended materials in cement. The replacement of Portland cement by limestone powder and BFS can lower the cost and enhance the greenness of concrete, since the production of these two materials needs less energy and causes less CO2 emission than Portland cement...

Simulation of connectivity of capillary porosity in hardening cement-based systems made of blended materials

In recent years, the durability of reinforced or prestressed concrete structures has become a main concern. A key parameter in durability predictions is the microstructure of the surface zone of concrete structures, i.e. the “covercrete”, more in particular the connectivity of the pores in the cement paste matrix. In this paper, the connectivity...

Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II: Properties of Steel Surface Layers

The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

Numerical simulation of the hydration process and the development of microstructure of self-compacting cement paste containing limestone as filler

Three-dimensional Microstructure Simulation Model of Cement Based Materials,

This paper describes a computer-based numerical model for the simulation of the development of microstructure during cement hydration. Special emphasis is on the algorithm for characterizing the pores. This includes the porosity and the pore size distribution and the topological properties of the porous network. In order to do so, a serial...